[PATCH 1/6] mdev: class id support

Jason Wang
Tue, 24 Sep 2019 11:20:27 -0000

On 2019/9/24 ??4:58, Parav Pandit wrote:
> Hi Jason,
>
>> -----Original Message-----
>> From: Jason Wang <jasowang at redhat.com>
>> Sent: Monday, September 23, 2019 8:03 AM
>> To: kvm at vger.kernel.org; linux-s390 at vger.kernel.org; linux-
>> kernel at vger.kernel.org; dri-devel at lists.freedesktop.org; intel-
>> gfx at lists.freedesktop.org; intel-gvt-dev at lists.freedesktop.org;
>> kwankhede at nvidia.com; alex.williamson at redhat.com; mst at
redhat.com;
>> tiwei.bie at intel.com
>> Cc: virtualization at lists.linux-foundation.org; netdev at
vger.kernel.org;
>> cohuck at redhat.com; maxime.coquelin at redhat.com;
>> cunming.liang at intel.com; zhihong.wang at intel.com;
>> rob.miller at broadcom.com; xiao.w.wang at intel.com;
>> haotian.wang at sifive.com; zhenyuw at linux.intel.com; zhi.a.wang at
intel.com;
>> jani.nikula at linux.intel.com; joonas.lahtinen at linux.intel.com;
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linux.ibm.com;
>> oberpar at linux.ibm.com; heiko.carstens at de.ibm.com; gor at
linux.ibm.com;
>> borntraeger at de.ibm.com; akrowiak at linux.ibm.com; freude at
linux.ibm.com;
>> lingshan.zhu at intel.com; Ido Shamay <idos at mellanox.com>;
>> eperezma at redhat.com; lulu at redhat.com; Parav Pandit
>> <parav at mellanox.com>; Jason Wang <jasowang at
redhat.com>
>> Subject: [PATCH 1/6] mdev: class id support
>>
>> Mdev bus only supports vfio driver right now, so it doesn't
implement match
>> method. But in the future, we may add drivers other than vfio, one
example is
>> virtio-mdev[1] driver. This means we need to add device class id
support in bus
>> match method to pair the mdev device and mdev driver correctly.
>>
>> So this patch adds id_table to mdev_driver and class_id for mdev parent
with
>> the match method for mdev bus.
>>
>> Signed-off-by: Jason Wang <jasowang at redhat.com>
>> ---
>>  Documentation/driver-api/vfio-mediated-device.rst |  7 +++++--
>>  drivers/gpu/drm/i915/gvt/kvmgt.c                  |  2 +-
>>  drivers/s390/cio/vfio_ccw_ops.c                   |  2 +-
>>  drivers/s390/crypto/vfio_ap_ops.c                 |  3 ++-
>>  drivers/vfio/mdev/mdev_core.c                     | 14 ++++++++++++--
>>  drivers/vfio/mdev/mdev_driver.c                   | 14 ++++++++++++++
>>  drivers/vfio/mdev/mdev_private.h                  |  1 +
>>  drivers/vfio/mdev/vfio_mdev.c                     |  6 ++++++
>>  include/linux/mdev.h                              |  7 ++++++-
>>  include/linux/mod_devicetable.h                   |  8 ++++++++
>>  samples/vfio-mdev/mbochs.c                        |  2 +-
>>  samples/vfio-mdev/mdpy.c                          |  2 +-
>>  samples/vfio-mdev/mtty.c                          |  2 +-
>>  13 files changed, 59 insertions(+), 11 deletions(-)
>>
>> diff --git a/Documentation/driver-api/vfio-mediated-device.rst
>> b/Documentation/driver-api/vfio-mediated-device.rst
>> index 25eb7d5b834b..0e052072e1d8 100644
>> --- a/Documentation/driver-api/vfio-mediated-device.rst
>> +++ b/Documentation/driver-api/vfio-mediated-device.rst
>> @@ -102,12 +102,14 @@ structure to represent a mediated device's
driver::
>>        * @probe: called when new device created
>>        * @remove: called when device removed
>>        * @driver: device driver structure
>> +      * @id_table: the ids serviced by this driver.
> No full stop at the end.


Will fix this.


>
>>        */
>>       struct mdev_driver {
>>  	     const char *name;
>>  	     int  (*probe)  (struct device *dev);
>>  	     void (*remove) (struct device *dev);
>>  	     struct device_driver    driver;
>> +	     const struct mdev_class_id *id_table;
>>       };
>>
>>  A mediated bus driver for mdev should use this structure in the
function calls
>> @@ -116,7 +118,7 @@ to register and unregister itself with the core
driver:
>>  * Register::
>>
>>      extern int  mdev_register_driver(struct mdev_driver *drv,
>> -				   struct module *owner);
>> +                                     struct module *owner);
>>
> Unrelated change in this patch.


Yes, will fix.


>
>>  * Unregister::
>>
>> @@ -163,7 +165,8 @@ A driver should use the mdev_parent_ops structure
in
>> the function call to  register itself with the mdev core driver::
>>
>>  	extern int  mdev_register_device(struct device *dev,
>> -	                                 const struct mdev_parent_ops *ops);
>> +	                                 const struct mdev_parent_ops *ops,
>> +	                                 u8 class_id);
>>
> Cover letter from Change-V2 says that it class_id changed from " use
u16 instead u8 for class id"
> But it is still u8 here?


Right, let me fix it in v2.


>
>>  However, the mdev_parent_ops structure is not required in the function
call
>> that a driver should use to unregister itself with the mdev core
driver::
>> diff --git a/drivers/gpu/drm/i915/gvt/kvmgt.c
>> b/drivers/gpu/drm/i915/gvt/kvmgt.c
>> index 23aa3e50cbf8..19d51a35f019 100644
>> --- a/drivers/gpu/drm/i915/gvt/kvmgt.c
>> +++ b/drivers/gpu/drm/i915/gvt/kvmgt.c
>> @@ -1625,7 +1625,7 @@ static int kvmgt_host_init(struct device *dev,
void
>> *gvt, const void *ops)
>>  		return -EFAULT;
>>  	intel_vgpu_ops.supported_type_groups = kvm_vgpu_type_groups;
>>
>> -	return mdev_register_device(dev, &intel_vgpu_ops);
>> +	return mdev_register_vfio_device(dev, &intel_vgpu_ops);
>>  }
>>
>>  static void kvmgt_host_exit(struct device *dev) diff --git
>> a/drivers/s390/cio/vfio_ccw_ops.c b/drivers/s390/cio/vfio_ccw_ops.c
index
>> f0d71ab77c50..246ff0f80944 100644
>> --- a/drivers/s390/cio/vfio_ccw_ops.c
>> +++ b/drivers/s390/cio/vfio_ccw_ops.c
>> @@ -588,7 +588,7 @@ static const struct mdev_parent_ops
>> vfio_ccw_mdev_ops = {
>>
>>  int vfio_ccw_mdev_reg(struct subchannel *sch)  {
>> -	return mdev_register_device(&sch->dev,
&vfio_ccw_mdev_ops);
>> +	return mdev_register_vfio_device(&sch->dev,
&vfio_ccw_mdev_ops);
>>  }
>>
>>  void vfio_ccw_mdev_unreg(struct subchannel *sch) diff --git
>> a/drivers/s390/crypto/vfio_ap_ops.c b/drivers/s390/crypto/vfio_ap_ops.c
>> index 5c0f53c6dde7..7487fc39d2c5 100644
>> --- a/drivers/s390/crypto/vfio_ap_ops.c
>> +++ b/drivers/s390/crypto/vfio_ap_ops.c
>> @@ -1295,7 +1295,8 @@ int vfio_ap_mdev_register(void)  {
>>  	atomic_set(&matrix_dev->available_instances,
>> MAX_ZDEV_ENTRIES_EXT);
>>
>> -	return mdev_register_device(&matrix_dev->device,
>> &vfio_ap_matrix_ops);
>> +	return mdev_register_vfio_device(&matrix_dev->device,
>> +					 &vfio_ap_matrix_ops);
>>  }
>>
>>  void vfio_ap_mdev_unregister(void)
>> diff --git a/drivers/vfio/mdev/mdev_core.c
b/drivers/vfio/mdev/mdev_core.c
>> index b558d4cfd082..a02c256a3514 100644
>> --- a/drivers/vfio/mdev/mdev_core.c
>> +++ b/drivers/vfio/mdev/mdev_core.c
>> @@ -135,11 +135,14 @@ static int mdev_device_remove_cb(struct device
>> *dev, void *data)
>>   * mdev_register_device : Register a device
>>   * @dev: device structure representing parent device.
>>   * @ops: Parent device operation structure to be registered.
>> + * @id: device id.
>>   *
> It device id here, but in below its class_id. Please make them uniform.


Yes, will fix.


>>   * Add device to list of registered parent devices.
>>   * Returns a negative value on error, otherwise 0.
>>   */
>> -int mdev_register_device(struct device *dev, const struct
mdev_parent_ops
>> *ops)
>> +int mdev_register_device(struct device *dev,
>> +			 const struct mdev_parent_ops *ops,
>> +			 u8 class_id)
>>  {
> u16 class_id?


Yes it is.


>
>>  	int ret;
>>  	struct mdev_parent *parent;
>> @@ -175,6 +178,7 @@ int mdev_register_device(struct device *dev, const
>> struct mdev_parent_ops *ops)
>>
>>  	parent->dev = dev;
>>  	parent->ops = ops;
>> +	parent->class_id = class_id;
>>
>>  	if (!mdev_bus_compat_class) {
>>  		mdev_bus_compat_class >>
class_compat_register("mdev_bus");
>> @@ -208,7 +212,13 @@ int mdev_register_device(struct device *dev, const
>> struct mdev_parent_ops *ops)
>>  		put_device(dev);
>>  	return ret;
>>  }
>> -EXPORT_SYMBOL(mdev_register_device);
>> +
>> +int mdev_register_vfio_device(struct device *dev,
>> +			      const struct mdev_parent_ops *ops) {
>> +	return mdev_register_device(dev, ops, MDEV_ID_VFIO); }
>> +EXPORT_SYMBOL(mdev_register_vfio_device);
>>
>>  /*
>>   * mdev_unregister_device : Unregister a parent device diff --git
>> a/drivers/vfio/mdev/mdev_driver.c b/drivers/vfio/mdev/mdev_driver.c
index
>> 0d3223aee20b..b70bbebc9dd3 100644
>> --- a/drivers/vfio/mdev/mdev_driver.c
>> +++ b/drivers/vfio/mdev/mdev_driver.c
>> @@ -69,8 +69,22 @@ static int mdev_remove(struct device *dev)
>>  	return 0;
>>  }
>>
>> +static int mdev_match(struct device *dev, struct device_driver *drv) {
>> +	unsigned int i;
>> +	struct mdev_device *mdev = to_mdev_device(dev);
>> +	struct mdev_driver *mdrv = to_mdev_driver(drv);
>> +	const struct mdev_class_id *ids = mdrv->id_table;
>> +
>> +	for (i = 0; ids[i].id; i++)
>> +		if (ids[i].id == mdev->parent->class_id)
>> +			return 1;
>> +	return 0;
>> +}
>> +
>>  struct bus_type mdev_bus_type = {
>>  	.name		= "mdev",
>> +	.match		= mdev_match,
>>  	.probe		= mdev_probe,
>>  	.remove		= mdev_remove,
>>  };
>> diff --git a/drivers/vfio/mdev/mdev_private.h
>> b/drivers/vfio/mdev/mdev_private.h
>> index 7d922950caaf..e58b07c866b1 100644
>> --- a/drivers/vfio/mdev/mdev_private.h
>> +++ b/drivers/vfio/mdev/mdev_private.h
>> @@ -22,6 +22,7 @@ struct mdev_parent {
>>  	struct list_head type_list;
>>  	/* Synchronize device creation/removal with parent unregistration */
>>  	struct rw_semaphore unreg_sem;
>> +	u8 class_id;
>>  };
>>
>>  struct mdev_device {
>> diff --git a/drivers/vfio/mdev/vfio_mdev.c
b/drivers/vfio/mdev/vfio_mdev.c
>> index 30964a4e0a28..fd2a4d9a3f26 100644
>> --- a/drivers/vfio/mdev/vfio_mdev.c
>> +++ b/drivers/vfio/mdev/vfio_mdev.c
>> @@ -120,10 +120,16 @@ static void vfio_mdev_remove(struct device *dev)
>>  	vfio_del_group_dev(dev);
>>  }
>>
>> +static struct mdev_class_id id_table[] = {
>> +	{ MDEV_ID_VFIO },
>> +	{ 0 },
>> +};
>> +
>>  static struct mdev_driver vfio_mdev_driver = {
>>  	.name	= "vfio_mdev",
>>  	.probe	= vfio_mdev_probe,
>>  	.remove	= vfio_mdev_remove,
>> +	.id_table = id_table,
>>  };
>>
>>  static int __init vfio_mdev_init(void)
>> diff --git a/include/linux/mdev.h b/include/linux/mdev.h index
>> 0ce30ca78db0..3ebae310f599 100644
>> --- a/include/linux/mdev.h
>> +++ b/include/linux/mdev.h
>> @@ -118,6 +118,7 @@ struct mdev_type_attribute mdev_type_attr_##_name
>> =		\
>>   * @probe: called when new device created
>>   * @remove: called when device removed
>>   * @driver: device driver structure
>> + * @id_table: the ids serviced by this driver.
>>   *
>>   **/
>>  struct mdev_driver {
>> @@ -125,6 +126,7 @@ struct mdev_driver {
>>  	int  (*probe)(struct device *dev);
>>  	void (*remove)(struct device *dev);
>>  	struct device_driver driver;
>> +	const struct mdev_class_id *id_table;
>>  };
>>
>>  #define to_mdev_driver(drv)	container_of(drv, struct mdev_driver,
driver)
>> @@ -135,7 +137,8 @@ const guid_t *mdev_uuid(struct mdev_device *mdev);
>>
>>  extern struct bus_type mdev_bus_type;
>>
>> -int mdev_register_device(struct device *dev, const struct
mdev_parent_ops
>> *ops);
>> +int mdev_register_vfio_device(struct device *dev,
>> +			      const struct mdev_parent_ops *ops);
>>  void mdev_unregister_device(struct device *dev);
>>
>>  int mdev_register_driver(struct mdev_driver *drv, struct module
*owner);
>> @@ -145,4 +148,6 @@ struct device *mdev_parent_dev(struct mdev_device
>> *mdev);  struct device *mdev_dev(struct mdev_device *mdev);  struct
>> mdev_device *mdev_from_dev(struct device *dev);
>>
>> +#define MDEV_ID_VFIO 1 /* VFIO device */
>> +
> Instead of define, please put them as enum
>
> enum mdev_class/device_id {
> 	MDEV_ID_VFIO = 1,
> 	/* New entries must be added here */
> };


Ok.


>
>>  #endif /* MDEV_H */
>> diff --git a/include/linux/mod_devicetable.h
b/include/linux/mod_devicetable.h
>> index 5714fd35a83c..f32c6e44fb1a 100644
>> --- a/include/linux/mod_devicetable.h
>> +++ b/include/linux/mod_devicetable.h
>> @@ -821,4 +821,12 @@ struct wmi_device_id {
>>  	const void *context;
>>  };
>>
>> +/**
>> + * struct mdev_class_id - MDEV device class identifier
>> + * @id: Used to identify a specific class of device, e.g vfio-mdev
device.
>> + */
>> +struct mdev_class_id {
>> +	__u16 id;
>> +};
> This is u16 as I guess you wanted as opposed to u8 in other places in
patch.


Right.

Thanks


>> +
>>  #endif /* LINUX_MOD_DEVICETABLE_H */
>> diff --git a/samples/vfio-mdev/mbochs.c b/samples/vfio-mdev/mbochs.c
index
>> ac5c8c17b1ff..71a4469be85d 100644
>> --- a/samples/vfio-mdev/mbochs.c
>> +++ b/samples/vfio-mdev/mbochs.c
>> @@ -1468,7 +1468,7 @@ static int __init mbochs_dev_init(void)
>>  	if (ret)
>>  		goto failed2;
>>
>> -	ret = mdev_register_device(&mbochs_dev, &mdev_fops);
>> +	ret = mdev_register_vfio_device(&mbochs_dev, &mdev_fops);
>>  	if (ret)
>>  		goto failed3;
>>
>> diff --git a/samples/vfio-mdev/mdpy.c b/samples/vfio-mdev/mdpy.c index
>> cc86bf6566e4..d3029dd27d91 100644
>> --- a/samples/vfio-mdev/mdpy.c
>> +++ b/samples/vfio-mdev/mdpy.c
>> @@ -775,7 +775,7 @@ static int __init mdpy_dev_init(void)
>>  	if (ret)
>>  		goto failed2;
>>
>> -	ret = mdev_register_device(&mdpy_dev, &mdev_fops);
>> +	ret = mdev_register_vfio_device(&mdpy_dev, &mdev_fops);
>>  	if (ret)
>>  		goto failed3;
>>
>> diff --git a/samples/vfio-mdev/mtty.c b/samples/vfio-mdev/mtty.c index
>> 92e770a06ea2..744c88a6b22c 100644
>> --- a/samples/vfio-mdev/mtty.c
>> +++ b/samples/vfio-mdev/mtty.c
>> @@ -1468,7 +1468,7 @@ static int __init mtty_dev_init(void)
>>  	if (ret)
>>  		goto failed2;
>>
>> -	ret = mdev_register_device(&mtty_dev.dev, &mdev_fops);
>> +	ret = mdev_register_vfio_device(&mtty_dev.dev, &mdev_fops);
>>  	if (ret)
>>  		goto failed3;
>>
>> --
>> 2.19.1